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/*
 * Copyright (c) 2012, Stephen Colebourne & Michael Nascimento Santos
 *
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are met:
 *
 *  * Redistributions of source code must retain the above copyright notice,
 *    this list of conditions and the following disclaimer.
 *
 *  * Redistributions in binary form must reproduce the above copyright notice,
 *    this list of conditions and the following disclaimer in the documentation
 *    and/or other materials provided with the distribution.
 *
 *  * Neither the name of JSR-310 nor the names of its contributors
 *    may be used to endorse or promote products derived from this software
 *    without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
 * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR
 * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
 * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
 * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
 * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
 * LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
 * NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
 * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */
package java.time.chrono;

import static java.time.temporal.ChronoField.ALIGNED_DAY_OF_WEEK_IN_MONTH;
import static java.time.temporal.ChronoField.ALIGNED_DAY_OF_WEEK_IN_YEAR;
import static java.time.temporal.ChronoField.ALIGNED_WEEK_OF_MONTH;
import static java.time.temporal.ChronoField.ALIGNED_WEEK_OF_YEAR;
import static java.time.temporal.ChronoField.DAY_OF_MONTH;
import static java.time.temporal.ChronoField.MONTH_OF_YEAR;
import static java.time.temporal.ChronoField.YEAR;

import java.io.DataInput;
import java.io.DataOutput;
import java.io.IOException;
import java.io.InvalidObjectException;
import java.io.ObjectInputStream;
import java.io.Serializable;
import java.time.Clock;
import java.time.DateTimeException;
import java.time.LocalDate;
import java.time.LocalTime;
import java.time.Period;
import java.time.ZoneId;
import java.time.temporal.ChronoField;
import java.time.temporal.TemporalAccessor;
import java.time.temporal.TemporalAdjuster;
import java.time.temporal.TemporalAmount;
import java.time.temporal.TemporalField;
import java.time.temporal.TemporalQuery;
import java.time.temporal.TemporalUnit;
import java.time.temporal.UnsupportedTemporalTypeException;
import java.time.temporal.ValueRange;
import java.util.Calendar;
import java.util.Objects;

import sun.util.calendar.CalendarDate;
import sun.util.calendar.LocalGregorianCalendar;

/**
 * A date in the Japanese Imperial calendar system.
 * <p>
 * This date operates using the {@linkplain JapaneseChronology Japanese Imperial calendar}.
 * This calendar system is primarily used in Japan.
 * <p>
 * The Japanese Imperial calendar system is the same as the ISO calendar system
 * apart from the era-based year numbering. The proleptic-year is defined to be
 * equal to the ISO proleptic-year.
 * <p>
 * Japan introduced the Gregorian calendar starting with Meiji 6.
 * Only Meiji and later eras are supported;
 * dates before Meiji 6, January 1 are not supported.
 * <p>
 * For example, the Japanese year "Heisei 24" corresponds to ISO year "2012".<br>
 * Calling {@code japaneseDate.get(YEAR_OF_ERA)} will return 24.<br>
 * Calling {@code japaneseDate.get(YEAR)} will return 2012.<br>
 * Calling {@code japaneseDate.get(ERA)} will return 2, corresponding to
 * {@code JapaneseChronology.ERA_HEISEI}.<br>
 *
 * <p>
 * This is a <a href="{@docRoot}/java/lang/doc-files/ValueBased.html">value-based</a>
 * class; use of identity-sensitive operations (including reference equality
 * ({@code ==}), identity hash code, or synchronization) on instances of
 * {@code JapaneseDate} may have unpredictable results and should be avoided.
 * The {@code equals} method should be used for comparisons.
 *
 * @implSpec This class is immutable and thread-safe.
 * @since 1.8
 */
public final class JapaneseDate
    extends ChronoLocalDateImpl<JapaneseDate>
    implements ChronoLocalDate, Serializable {

  /**
   * Serialization version.
   */
  private static final long serialVersionUID = -305327627230580483L;

  /**
   * The underlying ISO local date.
   */
  private final transient LocalDate isoDate;
  /**
   * The JapaneseEra of this date.
   */
  private transient JapaneseEra era;
  /**
   * The Japanese imperial calendar year of this date.
   */
  private transient int yearOfEra;

  /**
   * The first day supported by the JapaneseChronology is Meiji 6, January 1st.
   */
  static final LocalDate MEIJI_6_ISODATE = LocalDate.of(1873, 1, 1);

  //-----------------------------------------------------------------------

  /**
   * Obtains the current {@code JapaneseDate} from the system clock in the default time-zone.
   * <p>
   * This will query the {@link Clock#systemDefaultZone() system clock} in the default
   * time-zone to obtain the current date.
   * <p>
   * Using this method will prevent the ability to use an alternate clock for testing
   * because the clock is hard-coded.
   *
   * @return the current date using the system clock and default time-zone, not null
   */
  public static JapaneseDate now() {
    return now(Clock.systemDefaultZone());
  }

  /**
   * Obtains the current {@code JapaneseDate} from the system clock in the specified time-zone.
   * <p>
   * This will query the {@link Clock#system(ZoneId) system clock} to obtain the current date.
   * Specifying the time-zone avoids dependence on the default time-zone.
   * <p>
   * Using this method will prevent the ability to use an alternate clock for testing
   * because the clock is hard-coded.
   *
   * @param zone the zone ID to use, not null
   * @return the current date using the system clock, not null
   */
  public static JapaneseDate now(ZoneId zone) {
    return now(Clock.system(zone));
  }

  /**
   * Obtains the current {@code JapaneseDate} from the specified clock.
   * <p>
   * This will query the specified clock to obtain the current date - today.
   * Using this method allows the use of an alternate clock for testing.
   * The alternate clock may be introduced using {@linkplain Clock dependency injection}.
   *
   * @param clock the clock to use, not null
   * @return the current date, not null
   * @throws DateTimeException if the current date cannot be obtained
   */
  public static JapaneseDate now(Clock clock) {
    return new JapaneseDate(LocalDate.now(clock));
  }

  /**
   * Obtains a {@code JapaneseDate} representing a date in the Japanese calendar
   * system from the era, year-of-era, month-of-year and day-of-month fields.
   * <p>
   * This returns a {@code JapaneseDate} with the specified fields.
   * The day must be valid for the year and month, otherwise an exception will be thrown.
   * <p>
   * The Japanese month and day-of-month are the same as those in the
   * ISO calendar system. They are not reset when the era changes.
   * For example:
   * <pre>
   *  6th Jan Showa 64 = ISO 1989-01-06
   *  7th Jan Showa 64 = ISO 1989-01-07
   *  8th Jan Heisei 1 = ISO 1989-01-08
   *  9th Jan Heisei 1 = ISO 1989-01-09
   * </pre>
   *
   * @param era the Japanese era, not null
   * @param yearOfEra the Japanese year-of-era
   * @param month the Japanese month-of-year, from 1 to 12
   * @param dayOfMonth the Japanese day-of-month, from 1 to 31
   * @return the date in Japanese calendar system, not null
   * @throws DateTimeException if the value of any field is out of range, or if the day-of-month is
   * invalid for the month-year, or if the date is not a Japanese era
   */
  public static JapaneseDate of(JapaneseEra era, int yearOfEra, int month, int dayOfMonth) {
    Objects.requireNonNull(era, "era");
    LocalGregorianCalendar.Date jdate = JapaneseChronology.JCAL.newCalendarDate(null);
    jdate.setEra(era.getPrivateEra()).setDate(yearOfEra, month, dayOfMonth);
    if (!JapaneseChronology.JCAL.validate(jdate)) {
      throw new DateTimeException("year, month, and day not valid for Era");
    }
    LocalDate date = LocalDate.of(jdate.getNormalizedYear(), month, dayOfMonth);
    return new JapaneseDate(era, yearOfEra, date);
  }

  /**
   * Obtains a {@code JapaneseDate} representing a date in the Japanese calendar
   * system from the proleptic-year, month-of-year and day-of-month fields.
   * <p>
   * This returns a {@code JapaneseDate} with the specified fields.
   * The day must be valid for the year and month, otherwise an exception will be thrown.
   * <p>
   * The Japanese proleptic year, month and day-of-month are the same as those
   * in the ISO calendar system. They are not reset when the era changes.
   *
   * @param prolepticYear the Japanese proleptic-year
   * @param month the Japanese month-of-year, from 1 to 12
   * @param dayOfMonth the Japanese day-of-month, from 1 to 31
   * @return the date in Japanese calendar system, not null
   * @throws DateTimeException if the value of any field is out of range, or if the day-of-month is
   * invalid for the month-year
   */
  public static JapaneseDate of(int prolepticYear, int month, int dayOfMonth) {
    return new JapaneseDate(LocalDate.of(prolepticYear, month, dayOfMonth));
  }

  /**
   * Obtains a {@code JapaneseDate} representing a date in the Japanese calendar
   * system from the era, year-of-era and day-of-year fields.
   * <p>
   * This returns a {@code JapaneseDate} with the specified fields.
   * The day must be valid for the year, otherwise an exception will be thrown.
   * <p>
   * The day-of-year in this factory is expressed relative to the start of the year-of-era.
   * This definition changes the normal meaning of day-of-year only in those years
   * where the year-of-era is reset to one due to a change in the era.
   * For example:
   * <pre>
   *  6th Jan Showa 64 = day-of-year 6
   *  7th Jan Showa 64 = day-of-year 7
   *  8th Jan Heisei 1 = day-of-year 1
   *  9th Jan Heisei 1 = day-of-year 2
   * </pre>
   *
   * @param era the Japanese era, not null
   * @param yearOfEra the Japanese year-of-era
   * @param dayOfYear the chronology day-of-year, from 1 to 366
   * @return the date in Japanese calendar system, not null
   * @throws DateTimeException if the value of any field is out of range, or if the day-of-year is
   * invalid for the year
   */
  static JapaneseDate ofYearDay(JapaneseEra era, int yearOfEra, int dayOfYear) {
    Objects.requireNonNull(era, "era");
    CalendarDate firstDay = era.getPrivateEra().getSinceDate();
    LocalGregorianCalendar.Date jdate = JapaneseChronology.JCAL.newCalendarDate(null);
    jdate.setEra(era.getPrivateEra());
    if (yearOfEra == 1) {
      jdate.setDate(yearOfEra, firstDay.getMonth(), firstDay.getDayOfMonth() + dayOfYear - 1);
    } else {
      jdate.setDate(yearOfEra, 1, dayOfYear);
    }
    JapaneseChronology.JCAL.normalize(jdate);
    if (era.getPrivateEra() != jdate.getEra() || yearOfEra != jdate.getYear()) {
      throw new DateTimeException("Invalid parameters");
    }
    LocalDate localdate = LocalDate.of(jdate.getNormalizedYear(),
        jdate.getMonth(), jdate.getDayOfMonth());
    return new JapaneseDate(era, yearOfEra, localdate);
  }

  /**
   * Obtains a {@code JapaneseDate} from a temporal object.
   * <p>
   * This obtains a date in the Japanese calendar system based on the specified temporal.
   * A {@code TemporalAccessor} represents an arbitrary set of date and time information,
   * which this factory converts to an instance of {@code JapaneseDate}.
   * <p>
   * The conversion typically uses the {@link ChronoField#EPOCH_DAY EPOCH_DAY}
   * field, which is standardized across calendar systems.
   * <p>
   * This method matches the signature of the functional interface {@link TemporalQuery}
   * allowing it to be used as a query via method reference, {@code JapaneseDate::from}.
   *
   * @param temporal the temporal object to convert, not null
   * @return the date in Japanese calendar system, not null
   * @throws DateTimeException if unable to convert to a {@code JapaneseDate}
   */
  public static JapaneseDate from(TemporalAccessor temporal) {
    return JapaneseChronology.INSTANCE.date(temporal);
  }

  //-----------------------------------------------------------------------

  /**
   * Creates an instance from an ISO date.
   *
   * @param isoDate the standard local date, validated not null
   */
  JapaneseDate(LocalDate isoDate) {
    if (isoDate.isBefore(MEIJI_6_ISODATE)) {
      throw new DateTimeException("JapaneseDate before Meiji 6 is not supported");
    }
    LocalGregorianCalendar.Date jdate = toPrivateJapaneseDate(isoDate);
    this.era = JapaneseEra.toJapaneseEra(jdate.getEra());
    this.yearOfEra = jdate.getYear();
    this.isoDate = isoDate;
  }

  /**
   * Constructs a {@code JapaneseDate}. This constructor does NOT validate the given parameters,
   * and {@code era} and {@code year} must agree with {@code isoDate}.
   *
   * @param era the era, validated not null
   * @param year the year-of-era, validated
   * @param isoDate the standard local date, validated not null
   */
  JapaneseDate(JapaneseEra era, int year, LocalDate isoDate) {
    if (isoDate.isBefore(MEIJI_6_ISODATE)) {
      throw new DateTimeException("JapaneseDate before Meiji 6 is not supported");
    }
    this.era = era;
    this.yearOfEra = year;
    this.isoDate = isoDate;
  }

  //-----------------------------------------------------------------------

  /**
   * Gets the chronology of this date, which is the Japanese calendar system.
   * <p>
   * The {@code Chronology} represents the calendar system in use.
   * The era and other fields in {@link ChronoField} are defined by the chronology.
   *
   * @return the Japanese chronology, not null
   */
  @Override
  public JapaneseChronology getChronology() {
    return JapaneseChronology.INSTANCE;
  }

  /**
   * Gets the era applicable at this date.
   * <p>
   * The Japanese calendar system has multiple eras defined by {@link JapaneseEra}.
   *
   * @return the era applicable at this date, not null
   */
  @Override
  public JapaneseEra getEra() {
    return era;
  }

  /**
   * Returns the length of the month represented by this date.
   * <p>
   * This returns the length of the month in days.
   * Month lengths match those of the ISO calendar system.
   *
   * @return the length of the month in days
   */
  @Override
  public int lengthOfMonth() {
    return isoDate.lengthOfMonth();
  }

  @Override
  public int lengthOfYear() {
    Calendar jcal = Calendar.getInstance(JapaneseChronology.LOCALE);
    jcal.set(Calendar.ERA, era.getValue() + JapaneseEra.ERA_OFFSET);
    jcal.set(yearOfEra, isoDate.getMonthValue() - 1, isoDate.getDayOfMonth());
    return jcal.getActualMaximum(Calendar.DAY_OF_YEAR);
  }

  //-----------------------------------------------------------------------

  /**
   * Checks if the specified field is supported.
   * <p>
   * This checks if this date can be queried for the specified field.
   * If false, then calling the {@link #range(TemporalField) range} and
   * {@link #get(TemporalField) get} methods will throw an exception.
   * <p>
   * If the field is a {@link ChronoField} then the query is implemented here.
   * The supported fields are:
   * <ul>
   * <li>{@code DAY_OF_WEEK}
   * <li>{@code DAY_OF_MONTH}
   * <li>{@code DAY_OF_YEAR}
   * <li>{@code EPOCH_DAY}
   * <li>{@code MONTH_OF_YEAR}
   * <li>{@code PROLEPTIC_MONTH}
   * <li>{@code YEAR_OF_ERA}
   * <li>{@code YEAR}
   * <li>{@code ERA}
   * </ul>
   * All other {@code ChronoField} instances will return false.
   * <p>
   * If the field is not a {@code ChronoField}, then the result of this method
   * is obtained by invoking {@code TemporalField.isSupportedBy(TemporalAccessor)}
   * passing {@code this} as the argument.
   * Whether the field is supported is determined by the field.
   *
   * @param field the field to check, null returns false
   * @return true if the field is supported on this date, false if not
   */
  @Override
  public boolean isSupported(TemporalField field) {
    if (field == ALIGNED_DAY_OF_WEEK_IN_MONTH || field == ALIGNED_DAY_OF_WEEK_IN_YEAR ||
        field == ALIGNED_WEEK_OF_MONTH || field == ALIGNED_WEEK_OF_YEAR) {
      return false;
    }
    return ChronoLocalDate.super.isSupported(field);
  }

  @Override
  public ValueRange range(TemporalField field) {
    if (field instanceof ChronoField) {
      if (isSupported(field)) {
        ChronoField f = (ChronoField) field;
        switch (f) {
          case DAY_OF_MONTH:
            return ValueRange.of(1, lengthOfMonth());
          case DAY_OF_YEAR:
            return ValueRange.of(1, lengthOfYear());
          case YEAR_OF_ERA: {
            Calendar jcal = Calendar.getInstance(JapaneseChronology.LOCALE);
            jcal.set(Calendar.ERA, era.getValue() + JapaneseEra.ERA_OFFSET);
            jcal.set(yearOfEra, isoDate.getMonthValue() - 1, isoDate.getDayOfMonth());
            return ValueRange.of(1, jcal.getActualMaximum(Calendar.YEAR));
          }
        }
        return getChronology().range(f);
      }
      throw new UnsupportedTemporalTypeException("Unsupported field: " + field);
    }
    return field.rangeRefinedBy(this);
  }

  @Override
  public long getLong(TemporalField field) {
    if (field instanceof ChronoField) {
      // same as ISO:
      // DAY_OF_WEEK, DAY_OF_MONTH, EPOCH_DAY, MONTH_OF_YEAR, PROLEPTIC_MONTH, YEAR
      //
      // calendar specific fields
      // DAY_OF_YEAR, YEAR_OF_ERA, ERA
      switch ((ChronoField) field) {
        case ALIGNED_DAY_OF_WEEK_IN_MONTH:
        case ALIGNED_DAY_OF_WEEK_IN_YEAR:
        case ALIGNED_WEEK_OF_MONTH:
        case ALIGNED_WEEK_OF_YEAR:
          throw new UnsupportedTemporalTypeException("Unsupported field: " + field);
        case YEAR_OF_ERA:
          return yearOfEra;
        case ERA:
          return era.getValue();
        case DAY_OF_YEAR:
          Calendar jcal = Calendar.getInstance(JapaneseChronology.LOCALE);
          jcal.set(Calendar.ERA, era.getValue() + JapaneseEra.ERA_OFFSET);
          jcal.set(yearOfEra, isoDate.getMonthValue() - 1, isoDate.getDayOfMonth());
          return jcal.get(Calendar.DAY_OF_YEAR);
      }
      return isoDate.getLong(field);
    }
    return field.getFrom(this);
  }

  /**
   * Returns a {@code LocalGregorianCalendar.Date} converted from the given {@code isoDate}.
   *
   * @param isoDate the local date, not null
   * @return a {@code LocalGregorianCalendar.Date}, not null
   */
  private static LocalGregorianCalendar.Date toPrivateJapaneseDate(LocalDate isoDate) {
    LocalGregorianCalendar.Date jdate = JapaneseChronology.JCAL.newCalendarDate(null);
    sun.util.calendar.Era sunEra = JapaneseEra.privateEraFrom(isoDate);
    int year = isoDate.getYear();
    if (sunEra != null) {
      year -= sunEra.getSinceDate().getYear() - 1;
    }
    jdate.setEra(sunEra).setYear(year).setMonth(isoDate.getMonthValue())
        .setDayOfMonth(isoDate.getDayOfMonth());
    JapaneseChronology.JCAL.normalize(jdate);
    return jdate;
  }

  //-----------------------------------------------------------------------
  @Override
  public JapaneseDate with(TemporalField field, long newValue) {
    if (field instanceof ChronoField) {
      ChronoField f = (ChronoField) field;
      if (getLong(f) == newValue) {  // getLong() validates for supported fields
        return this;
      }
      switch (f) {
        case YEAR_OF_ERA:
        case YEAR:
        case ERA: {
          int nvalue = getChronology().range(f).checkValidIntValue(newValue, f);
          switch (f) {
            case YEAR_OF_ERA:
              return this.withYear(nvalue);
            case YEAR:
              return with(isoDate.withYear(nvalue));
            case ERA: {
              return this.withYear(JapaneseEra.of(nvalue), yearOfEra);
            }
          }
        }
      }
      // YEAR, PROLEPTIC_MONTH and others are same as ISO
      return with(isoDate.with(field, newValue));
    }
    return super.with(field, newValue);
  }

  /**
   * {@inheritDoc}
   *
   * @throws DateTimeException {@inheritDoc}
   * @throws ArithmeticException {@inheritDoc}
   */
  @Override
  public JapaneseDate with(TemporalAdjuster adjuster) {
    return super.with(adjuster);
  }

  /**
   * {@inheritDoc}
   *
   * @throws DateTimeException {@inheritDoc}
   * @throws ArithmeticException {@inheritDoc}
   */
  @Override
  public JapaneseDate plus(TemporalAmount amount) {
    return super.plus(amount);
  }

  /**
   * {@inheritDoc}
   *
   * @throws DateTimeException {@inheritDoc}
   * @throws ArithmeticException {@inheritDoc}
   */
  @Override
  public JapaneseDate minus(TemporalAmount amount) {
    return super.minus(amount);
  }
  //-----------------------------------------------------------------------

  /**
   * Returns a copy of this date with the year altered.
   * <p>
   * This method changes the year of the date.
   * If the month-day is invalid for the year, then the previous valid day
   * will be selected instead.
   * <p>
   * This instance is immutable and unaffected by this method call.
   *
   * @param era the era to set in the result, not null
   * @param yearOfEra the year-of-era to set in the returned date
   * @return a {@code JapaneseDate} based on this date with the requested year, never null
   * @throws DateTimeException if {@code year} is invalid
   */
  private JapaneseDate withYear(JapaneseEra era, int yearOfEra) {
    int year = JapaneseChronology.INSTANCE.prolepticYear(era, yearOfEra);
    return with(isoDate.withYear(year));
  }

  /**
   * Returns a copy of this date with the year-of-era altered.
   * <p>
   * This method changes the year-of-era of the date.
   * If the month-day is invalid for the year, then the previous valid day
   * will be selected instead.
   * <p>
   * This instance is immutable and unaffected by this method call.
   *
   * @param year the year to set in the returned date
   * @return a {@code JapaneseDate} based on this date with the requested year-of-era, never null
   * @throws DateTimeException if {@code year} is invalid
   */
  private JapaneseDate withYear(int year) {
    return withYear(getEra(), year);
  }

  //-----------------------------------------------------------------------
  @Override
  JapaneseDate plusYears(long years) {
    return with(isoDate.plusYears(years));
  }

  @Override
  JapaneseDate plusMonths(long months) {
    return with(isoDate.plusMonths(months));
  }

  @Override
  JapaneseDate plusWeeks(long weeksToAdd) {
    return with(isoDate.plusWeeks(weeksToAdd));
  }

  @Override
  JapaneseDate plusDays(long days) {
    return with(isoDate.plusDays(days));
  }

  @Override
  public JapaneseDate plus(long amountToAdd, TemporalUnit unit) {
    return super.plus(amountToAdd, unit);
  }

  @Override
  public JapaneseDate minus(long amountToAdd, TemporalUnit unit) {
    return super.minus(amountToAdd, unit);
  }

  @Override
  JapaneseDate minusYears(long yearsToSubtract) {
    return super.minusYears(yearsToSubtract);
  }

  @Override
  JapaneseDate minusMonths(long monthsToSubtract) {
    return super.minusMonths(monthsToSubtract);
  }

  @Override
  JapaneseDate minusWeeks(long weeksToSubtract) {
    return super.minusWeeks(weeksToSubtract);
  }

  @Override
  JapaneseDate minusDays(long daysToSubtract) {
    return super.minusDays(daysToSubtract);
  }

  private JapaneseDate with(LocalDate newDate) {
    return (newDate.equals(isoDate) ? this : new JapaneseDate(newDate));
  }

  @Override        // for javadoc and covariant return type
  @SuppressWarnings("unchecked")
  public final ChronoLocalDateTime<JapaneseDate> atTime(LocalTime localTime) {
    return (ChronoLocalDateTime<JapaneseDate>) super.atTime(localTime);
  }

  @Override
  public ChronoPeriod until(ChronoLocalDate endDate) {
    Period period = isoDate.until(endDate);
    return getChronology().period(period.getYears(), period.getMonths(), period.getDays());
  }

  @Override  // override for performance
  public long toEpochDay() {
    return isoDate.toEpochDay();
  }

  //-------------------------------------------------------------------------

  /**
   * Compares this date to another date, including the chronology.
   * <p>
   * Compares this {@code JapaneseDate} with another ensuring that the date is the same.
   * <p>
   * Only objects of type {@code JapaneseDate} are compared, other types return false.
   * To compare the dates of two {@code TemporalAccessor} instances, including dates
   * in two different chronologies, use {@link ChronoField#EPOCH_DAY} as a comparator.
   *
   * @param obj the object to check, null returns false
   * @return true if this is equal to the other date
   */
  @Override  // override for performance
  public boolean equals(Object obj) {
    if (this == obj) {
      return true;
    }
    if (obj instanceof JapaneseDate) {
      JapaneseDate otherDate = (JapaneseDate) obj;
      return this.isoDate.equals(otherDate.isoDate);
    }
    return false;
  }

  /**
   * A hash code for this date.
   *
   * @return a suitable hash code based only on the Chronology and the date
   */
  @Override  // override for performance
  public int hashCode() {
    return getChronology().getId().hashCode() ^ isoDate.hashCode();
  }

  //-----------------------------------------------------------------------

  /**
   * Defend against malicious streams.
   *
   * @param s the stream to read
   * @throws InvalidObjectException always
   */
  private void readObject(ObjectInputStream s) throws InvalidObjectException {
    throw new InvalidObjectException("Deserialization via serialization delegate");
  }

  /**
   * Writes the object using a
   * <a href="../../../serialized-form.html#java.time.chrono.Ser">dedicated serialized form</a>.
   *
   * @return the instance of {@code Ser}, not null
   * @serialData <pre>
   *  out.writeByte(4);                 // identifies a JapaneseDate
   *  out.writeInt(get(YEAR));
   *  out.writeByte(get(MONTH_OF_YEAR));
   *  out.writeByte(get(DAY_OF_MONTH));
   * </pre>
   */
  private Object writeReplace() {
    return new Ser(Ser.JAPANESE_DATE_TYPE, this);
  }

  void writeExternal(DataOutput out) throws IOException {
    // JapaneseChronology is implicit in the JAPANESE_DATE_TYPE
    out.writeInt(get(YEAR));
    out.writeByte(get(MONTH_OF_YEAR));
    out.writeByte(get(DAY_OF_MONTH));
  }

  static JapaneseDate readExternal(DataInput in) throws IOException {
    int year = in.readInt();
    int month = in.readByte();
    int dayOfMonth = in.readByte();
    return JapaneseChronology.INSTANCE.date(year, month, dayOfMonth);
  }

}
